Richard A.
Clarke makes assertions in his book Against All
Enemies that can be easily checked against external
and unambiguous sources. Is Clarke truthful in
verifiable assertions he makes?

Answer:

No, in at least one instance Clarke totally fabricates
a position he attributes to Laurie Mylroie, author of
Study Of Revenge (2000), and then he use his
own fabrication to discredit that author's position.

On p.95 of his Against All Enemies, Clarke
states that "author" Laurie Mylroie
had asserted that the real "Ramzi Yousef was not
in the federal Metropolitan Detention Center in Manhattan
but lounging at the right hand of Saddam Hussein in
Baghdad." He then debunks this "thesis"
by stating that, in fact, Ramzi Yousef "had been
in a U.S. jail for years," which was true.

Obviously, if Yousef had been in prison in America,
he could not be in Baghdad at the right hand of Saddam,
and Mylroie's theory would be demonstratively untrue--
a discreditation Clarke considers important enough to
feature on the dust jacket of his book, noting that
prior to 9-11 "[Paul] Wolfowitz was actually spouting
the totally discredited Laurie Mylroie theory."
The problem here is that
the straw man Clarke demolishes is an invention entirely
of his own creation. Mylroie did not write anything
remotely like it before 9-11 (or after it).
On the contrary, she explicitly states on p. 212 of
her book Study Of Revenge, "Ramzi Yousef
was arrested and returned to the U.S. on February 7,
1995." While she questions the provenance
of documents he used prior to his capture in 1995, she
does not claim in her book or any other writing that
Yousef resides anywhere but a maximum security federal
prison.
Clarke himself makes up the
absurd assertion Yousef was in Baghdad with Saddam,
falsely attributes it to Mylroie, then uses it to discredit
Mylroie.

Collateral
question:

Why Did Clarke go to such extreme lengths-- including
a blatant fabrication-- to discredit Mylroie's book?